Coordinated multipoint transmission/reception (Coordinated Multi-Point transmission and reception, CoMP) is a technology that is provided in Long Term Evolution (Long Term Evolution-Advanced, LTE-A) and that can effectively improve a system capacity of a wireless network. Coordinated scheduling and joint coding and decoding are performed for user data involved in CoMP, which can effectively improve an interference characteristic of a cell edge user, and can improve transmission efficiency for the cell edge user so as to improve transmission efficiency of an entire system.
For a CoMP application mode such as coordinated scheduling (Coordinated Scheduling, CS) or joint processing (Joint Processing, JP), uplink and downlink CoMP user data is generally aggregated to one central processing node for processing. Processing performed on CoMP user data by the central processing node includes scheduling, joint coding, joint decoding, or the like.
In a cloud radio access network (Cloud Radio Access Network, CRAN) architecture shown in FIG. 1, a central processing node is located in a baseband processing unit center (Base Band Unit center, BBU center), and the central processing node is connected to multiple remote radio units (Remote Radio Unit, RRU) by using a common public radio interface (Common Public Radio Interface, CPRI). The RRU has a radio frequency function. An IQ baseband signal is transmitted between the BBU center and each RRU, and a data transmission amount is relatively large. User data in a coverage area of each RRU needs to be received or sent by using an S1 interface of the BBU center; therefore, a transmission bottleneck is likely to result.
In a hybrid layer 1 (Hybrid L1) architecture shown in FIG. 2, a central processing node is located in a BBU center, and is connected to multiple evolved RRUs (evolved RRU, eRRU) by using a packet transport network (Packet Transport Network, PTN). The eRRU has a radio frequency function and a baseband compression function. Therefore, a baseband signal is transmitted between the BBU center and the eRRU after being compressed, which can reduce a data transmission amount compared with a CRAN. However, CoMP user data in a coverage area of each eRRU still needs to be received or sent by using an S1 interface of the BBU center; therefore, a transmission bottleneck is still present.